An audio playback system generates output signals for multiple channels of acoustic transducers by applying a rendering matrix to data representing the aural content and spatial characteristics of audio objects, so that the resulting sound field creates accurate listener impressions of the spatial characteristics. Matrix coefficients are updated to render moving objects. Discontinuous updates of the rendering matrix coefficients are controlled according to psychoacoustic principles to reduce audible artifacts. The updates may also be managed to control the amount of data needed to perform the updates.